At 9.30 a.m. an explosion tore through the Brunner mine in Westland’s Grey Valley. Two men sent underground to investigate were later found unconscious from black damp, a suffocating mixture of nitrogen and carbon dioxide.
Rescuers began bringing out bodies around 11 a.m. The noxious gases took their toll on those in the rescue parties, many of whom collapsed and had to be carried out.
The final death toll was 65 – almost half of Brunner’s underground work force. This remains New Zealand’s deadliest industrial accident.
Fifty-three of the victims were buried in the Stillwater cemetery, 33 of them in a single grave. The funeral procession stretched 800 metres.
The official enquiry determined that the cause was the detonating of a charge in a part of the mine where no one should have been working. However, some experienced miners claimed that firedamp – methane gas produced by coal – had accumulated and not been cleared by an ineffectual ventilation system.